• Summary
• Text account
• Data table and detailed info
• Distribution map
• Reference and further resources

Taxonomic source(s)
del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A. and Fishpool, L.D.C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Volume 1: Non-passerines. Lynx Edicions BirdLife International, Barcelona, Spain and Cambridge, UK.

Red List criteria met

Critically Endangered	Endangered	Vulnerable
-	B1ac(iv)	B1ac(iv); D1+2

Red List history

Year	Category	Criteria
2018	Critically Endangered	B1ac(iv)
2016	Critically Endangered	B1ac(iv)
2015	Critically Endangered	B1ac(iv)
2013	Critically Endangered	B1ac(iv)
2012	Critically Endangered	B1ac(iv)
2010	Critically Endangered	B1a+c(iv)
2009	Critically Endangered	B1a+c(iv)
2008	Critically Endangered
2006	Critically Endangered
2004	Critically Endangered
2000	Vulnerable
1996	Vulnerable
1994	Vulnerable
1988	Threatened

Migratory status	not a migrant	Forest dependency	does not normally occur in forest
Land-mass type		Average mass	-

	Estimate	Data quality
Extent of Occurrence (breeding/resident)	2 km2	medium
Number of locations	2	-
Severely fragmented?	no	-

	Estimate	Data quality	Derivation	Year of estimate
Population size	500-680 mature individuals	good	estimated	2010
Population trend	increasing	good	observed	1996-2017
Rate of change over the past 10 years/3 generations (longer of the two periods)	1-19%	-	-	-
Rate of change over the future 10 years/3 generations (longer of the two periods)	1-19%	-	-	-
Rate of change over the past & future 10 years/3 generations (longer of the two periods)	1-19%	-	-	-
Generation length	6.5 years	-	-	-
Number of subpopulations	2	-	-	-
Percentage of mature individuals in largest subpopulation	1-89%	-	-	-

Population justification: The total population on Laysan Island was estimated at 521 birds (95% CI: 492-549) in 2010, with probably over 400 individuals (between 268 and 473) on Midway in 2010 (M. Reynolds in litt. 2011). Twenty-eight individuals were translocated to Kure Atoll in 2014. This suggests that the population numbers c.500-680 mature individuals in total.

Trend justification: The population on Laysan Island has increased gradually since a low during the early 20th century, owing to the eradication of invasive alien taxa; however, it has fluctuated between 100 and ~700 birds in the last two decades. Population estimates for the species on Laysan Island indicate that it had been increasing between 1994 and 2010, although apparently the trend has not been consistent (Seavy et al. 2009, M. Reynolds in litt. 2011); however, the species appears to have suffered a c.50% decline in its adult population on Laysan following the winter storms and tsunami of early 2011 (J. R. Walters in litt. 2013). A second population established on Midway Atoll in 2004/2005 quadrupled in three years (Reynolds et al. 2007), but suffered a setback when over 160 birds were killed in an outbreak of avian botulism in August 2008 (M. Reynolds in litt. 2008). An outbreak of this disease has occurred every year since (M. Reynolds in litt. 2011, 2012, J. R. Walters in litt. 2011). Despite this, the overall population is estimated to have increased at a rate of under 20% over the last ten years.

Country/Territory	Presence	Origin	Resident	Breeding visitor	Non-breeding visitor	Passage migrant
USA	extant	native	yes

Country/Territory	IBA Name
USA	Northwestern Hawaiian Islands

Habitat (level 1)	Habitat (level 2)	Importance	Occurrence
Marine Coastal/Supratidal	Coastal Brackish/Saline Lagoons/Marine Lakes	major	resident
Marine Coastal/Supratidal	Coastal Freshwater Lakes	suitable	resident
Marine Intertidal	Mud Flats and Salt Flats	marginal	resident
Shrubland	Subtropical/Tropical Dry	major	resident
Altitude		Occasional altitudinal limits

Threat (level 1)	Threat (level 2)	Impact and Stresses
Biological resource use	Hunting & trapping terrestrial animals - Intentional use (species is the target)	Timing		Scope		Severity		Impact
		Past, Unlikely to Return		Whole (>90%)		Very Rapid Declines		Past Impact
		Stresses Species mortality
Climate change & severe weather	Droughts	Timing		Scope		Severity		Impact
		Past, Likely to Return		Whole (>90%)		Rapid Declines		Past Impact
		Stresses Ecosystem degradation, Reduced reproductive success, Species mortality
Climate change & severe weather	Habitat shifting & alteration	Timing		Scope		Severity		Impact
		Future		Whole (>90%)		Unknown		Unknown
		Stresses Indirect ecosystem effects, Ecosystem degradation
Climate change & severe weather	Storms & flooding	Timing		Scope		Severity		Impact
		Future		Whole (>90%)		Rapid Declines		Medium Impact: 6
		Stresses Ecosystem degradation
Invasive and other problematic species, genes & diseases	Invasive non-native/alien species/diseases - Cenchrus echinatus	Timing		Scope		Severity		Impact
		Past, Likely to Return		Whole (>90%)		Slow, Significant Declines		Past Impact
		Stresses Ecosystem degradation
Invasive and other problematic species, genes & diseases	Invasive non-native/alien species/diseases - Clostridium botulinum	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Causing/Could cause fluctuations		Low Impact: 5
		Stresses Species mortality
Invasive and other problematic species, genes & diseases	Invasive non-native/alien species/diseases - Echinuria uncinata	Timing		Scope		Severity		Impact
		Ongoing		Whole (>90%)		Negligible declines		Medium Impact: 6
		Stresses Species mortality
Invasive and other problematic species, genes & diseases	Invasive non-native/alien species/diseases - Named species	Timing		Scope		Severity		Impact
		Past, Likely to Return		Majority (50-90%)		Rapid Declines		Past Impact
		Stresses Species mortality
Invasive and other problematic species, genes & diseases	Invasive non-native/alien species/diseases - Oryctolagus cuniculus	Timing		Scope		Severity		Impact
		Past, Unlikely to Return		Whole (>90%)		Very Rapid Declines		Past Impact
		Stresses Ecosystem degradation
Invasive and other problematic species, genes & diseases	Invasive non-native/alien species/diseases - Pheidole megacephala	Timing		Scope		Severity		Impact
		Ongoing		Majority (50-90%)		Negligible declines		Low Impact: 5
		Stresses Competition
Invasive and other problematic species, genes & diseases	Invasive non-native/alien species/diseases - Rattus exulans	Timing		Scope		Severity		Impact
		Past, Unlikely to Return		Majority (50-90%)		Very Rapid Declines		Past Impact
		Stresses Species mortality
Invasive and other problematic species, genes & diseases	Problematic native species/diseases - Unspecified species	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Negligible declines		Low Impact: 4
		Stresses Species mortality

Purpose	Scale
Food - human	subsistence, national
Food - human	subsistence, national
Pets/display animals, horticulture	international
Pets/display animals, horticulture	international

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Recommended citation
BirdLife International (2024) Species factsheet: Laysan Duck Anas laysanensis. Downloaded from https://datazone.birdlife.org/species/factsheet/laysan-duck-anas-laysanensis on 22/12/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from https://datazone.birdlife.org/species/search on 22/12/2024.